Terracotta Army

In 1974, farmers digging a well near Xi'an uncovered fragments of a clay figure that led to the discovery of one of the largest archaeological finds of the 20th century: an estimated 8,000 life-sized terracotta soldiers, along with horses, chariots, and bronze weapons, buried in pits roughly 1.5 kilometres east of the tomb mound of Qin Shi Huang, who unified China and became its first emperor in 221 BCE. Each soldier's face appears individually modelled, with distinct hairstyles, expressions, and even ear shapes, suggesting either a vast number of unique sculptors or a modular system of interchangeable parts assembled in combination — researchers continue to debate which.

The army was buried to guard the emperor in the afterlife, but the emperor's own tomb mound, roughly 1.5 km away, has never been excavated. The 1st-century BCE historian Sima Qian, writing about a century after the emperor's death, described a vast subterranean palace containing models of palaces and the empire's geography, with rivers and seas of flowing mercury maintained in motion by mechanical means, and crossbow traps to kill intruders. Soil samples taken from the area of the tomb mound in the 1980s showed mercury concentrations significantly higher than surrounding areas, lending some support to Sima Qian's account. Chinese authorities have so far declined to open the tomb, citing both the toxicity of any mercury present and a desire to wait for conservation techniques capable of preserving artefacts that have been sealed for over two millennia — a lesson learned after the original paint on excavated terracotta figures was found to flake away and fade within minutes of exposure to air.